A gable top type or a brick type paper container for liquid which uses paper as its base material is formed by use of a laminated body in which various kinds of film materials are laminated to ensure the sealing performance, shelf life, rigidity or strength of the container. Specification of the laminated body differs for refrigerated distribution type and room temperature distribution, which includes one that enables long-term distribution, and is designed depending on the content and disinfecting method thereof, packaging method, set expiration date, or the like. Structure of packaging material for a conventional paper container for liquid such as milk used for refrigerated distribution (chilled distribution) is principally composed of low density polyethylene/paper/low density polyethylene, and since low density polyethylene (hereinafter referred to as LDPE) has good laminate workability when used as a sealant that forms a laminated body and heat-sealing properties when used to form a container, it is most commonly used. Especially for dairy products, additive-free LDPE which complies with ministerial ordinance regarding milk and the like is used.
However, it has a problem that when used as a paper container for liquid such as milk for refrigerated distribution (chilled distribution) and when the distance for distribution becomes long, breakage or leakage due to shocks occurs, which means that the structure of the material is not sufficient enough. To solve the problem, a paper container for liquid that uses a material adopting a structure of using linear low density polyethylene (hereinafter referred to as LLDPE) for a layer to be in contact with the liquid in order to increase strength against shocks or the like has been proposed (for example, refer to Patent Literature 1).
Patent Literature 1: Japanese Patent Unexamined Publication No. 2000-33679 (JP 2000-33679 A)